the two suspects brought a convenience store near the massachusetts institute of technology on thursday night. shortly afterwards, they exchanged fire with police and one of them managed to escape. the suspect at large is this man, dzhokhar tsarnaev. his brother, tamerlan, on the left, died this morning from gunshot wounds. the pair are immigrants, ethnic chechens, who were living in the u.s. their uncle says the brothers have brought shame on the family. he gave a public message to his nephews still in hiding. >> i say, dzhokhar , if you are alive, turn yourself in and ask for forgiveness from the victims whom you injured, and for those who are left, ask these people. >> schools remain closed. boston's public transit system has been shut down, and even the city's airspace has been partially closed. the entire city is on lockdown. >> let's go live to washington for the latest on the story. max, can you tell us more about the suspects? there's a lot of questions right now. are they the sole suspect? >> there was the idea or the rumor of a third suspect floating around for a while, at lea